vkGetMicromapBuildSizesEXT(3)

Name

vkGetMicromapBuildSizesEXT - Retrieve the required size for a micromap

C Specification

To get the build sizes for a micromap, call:

// Provided by VK_EXT_opacity_micromap
void vkGetMicromapBuildSizesEXT(
    VkDevice                                    device,
    VkAccelerationStructureBuildTypeKHR         buildType,
    const VkMicromapBuildInfoEXT*               pBuildInfo,
    VkMicromapBuildSizesInfoEXT*                pSizeInfo);

Parameters

device is the logical device that will be used for creating the micromap.
buildType defines whether host or device operations (or both) are being queried for.
pBuildInfo is a pointer to a VkMicromapBuildInfoEXT structure describing parameters of a build operation.
pSizeInfo is a pointer to a VkMicromapBuildSizesInfoEXT structure which returns the size required for a micromap and the sizes required for the scratch buffers, given the build parameters. The size requirements for a scratch buffer may be zero.

Description

The dstMicromap and mode members of pBuildInfo are ignored. Any VkDeviceOrHostAddressKHR members of pBuildInfo are ignored by this command.

A micromap created with the micromapSize returned by this command supports any build with a VkMicromapBuildInfoEXT structure subject to the following properties:

The build command is a host build command, and buildType is VK_ACCELERATION_STRUCTURE_BUILD_TYPE_HOST_KHR or VK_ACCELERATION_STRUCTURE_BUILD_TYPE_HOST_OR_DEVICE_KHR
The build command is a device build command, and buildType is VK_ACCELERATION_STRUCTURE_BUILD_TYPE_DEVICE_KHR or VK_ACCELERATION_STRUCTURE_BUILD_TYPE_HOST_OR_DEVICE_KHR
For VkMicromapBuildInfoEXT:
- Its type, and flags members are equal to pBuildInfo->type and pBuildInfo->flags, respectively.
- The sum of usage information in either pUsageCounts or ppUsageCounts is equal to the sum of usage information in either pBuildInfo->pUsageCounts or pBuildInfo->ppUsageCounts.

Similarly, the buildScratchSize value will support any build command specifying the VK_BUILD_MICROMAP_MODE_BUILD_EXT mode under the above conditions.

Valid Usage

VUID-vkGetMicromapBuildSizesEXT-dstMicromap-09180
VkMicromapBuildInfoEXT::dstMicromap must have been created from device
VUID-vkGetMicromapBuildSizesEXT-micromap-07439
The micromap feature must be enabled
VUID-vkGetMicromapBuildSizesEXT-device-07440
If device was created with multiple physical devices, then the bufferDeviceAddressMultiDevice feature must be enabled

Valid Usage (Implicit)

VUID-vkGetMicromapBuildSizesEXT-device-parameter
device must be a valid VkDevice handle
VUID-vkGetMicromapBuildSizesEXT-buildType-parameter
buildType must be a valid VkAccelerationStructureBuildTypeKHR value
VUID-vkGetMicromapBuildSizesEXT-pBuildInfo-parameter
pBuildInfo must be a valid pointer to a valid VkMicromapBuildInfoEXT structure
VUID-vkGetMicromapBuildSizesEXT-pSizeInfo-parameter
pSizeInfo must be a valid pointer to a VkMicromapBuildSizesInfoEXT structure

Document Notes

For more information, see the Vulkan Specification.

This page is extracted from the Vulkan Specification. Fixes and changes should be made to the Specification, not directly.